/**
 * xlsx导出方法文件
 * 需要安装依赖包 npm i xlsx file-saver -S
 */
import XLSX from 'xlsx' // excel数据处理
import FileSaver from 'file-saver' // 文件处理

function isArrayFn(value) {
  if (typeof Array.isArray === 'function') {
    return Array.isArray(value)
  } else {
    return Object.prototype.toString.call(value) === '[object Array]'
  }
}

function generateArray(table) {
  var out = []
  var rows = table.querySelectorAll('tr')
  var ranges = []
  for (var R = 0; R < rows.length; ++R) {
    var outRow = []
    var row = rows[R]
    var columns = row.querySelectorAll('td')
    for (var C = 0; C < columns.length; ++C) {
      var cell = columns[C]
      var colspan = cell.getAttribute('colspan')
      var rowspan = cell.getAttribute('rowspan')
      var cellValue = cell.innerText
      if (cellValue !== '' && cellValue == +cellValue) cellValue = +cellValue

      //Skip ranges
      ranges.forEach(function (range) {
        if (R >= range.s.r && R <= range.e.r && outRow.length >= range.s.c && outRow.length <= range.e.c) {
          for (var i = 0; i <= range.e.c - range.s.c; ++i) outRow.push(null)
        }
      })

      //Handle Row Span
      if (rowspan || colspan) {
        rowspan = rowspan || 1
        colspan = colspan || 1
        ranges.push({
          s: {
            r: R,
            c: outRow.length,
          },
          e: {
            r: R + rowspan - 1,
            c: outRow.length + colspan - 1,
          },
        })
      }
      //Handle Value
      outRow.push(cellValue !== '' ? cellValue : null)

      //Handle Colspan
      if (colspan) for (var k = 0; k < colspan - 1; ++k) outRow.push(null)
    }
    out.push(outRow)
  }
  return [out, ranges]
}

function datenum(v, date1904) {
  if (date1904) v += 1462
  var epoch = Date.parse(v)
  return (epoch - new Date(Date.UTC(1899, 11, 30))) / (24 * 60 * 60 * 1000)
}

function sheet_from_array_of_arrays(data, opts) {
  var ws = {}
  var range = {
    s: {
      c: 10000000,
      r: 10000000,
    },
    e: {
      c: 0,
      r: 0,
    },
  }
  for (var R = 0; R != data.length; ++R) {
    for (var C = 0; C != data[R].length; ++C) {
      if (range.s.r > R) range.s.r = R
      if (range.s.c > C) range.s.c = C
      if (range.e.r < R) range.e.r = R
      if (range.e.c < C) range.e.c = C
      var cell = {
        v: data[R][C],
      }
      if (cell.v == null) continue
      var cell_ref = XLSX.utils.encode_cell({
        c: C,
        r: R,
      })

      if (typeof cell.v === 'number') cell.t = 'n'
      else if (typeof cell.v === 'boolean') cell.t = 'b'
      else if (cell.v instanceof Date) {
        cell.t = 'n'
        cell.z = XLSX.SSF._table[14]
        cell.v = datenum(cell.v)
      } else cell.t = 's'

      ws[cell_ref] = cell
    }
  }
  if (range.s.c < 10000000) ws['!ref'] = XLSX.utils.encode_range(range)
  return ws
}

function Workbook() {
  if (!(this instanceof Workbook)) return new Workbook()
  this.SheetNames = []
  this.Sheets = {}
}

function s2ab(s) {
  var buf = new ArrayBuffer(s.length)
  var view = new Uint8Array(buf)
  for (var i = 0; i != s.length; ++i) view[i] = s.charCodeAt(i) & 0xff
  return buf
}

/**
 * 格式化数据
 * @param filterVal 表头在数据中的对应key数组
 * @param jsonData 需要导出表格数据
 */
function formatJson(filterVal, jsonData) {
  return jsonData.map((v) => {
    return filterVal.map((j) => {
      if (v[j] === null || v[j] === undefined) return ''
      return v[j].toString()
    })
  })
}

/**
 * 通过table标签渲染导出表格
 * @param id 需要导出表格的ID
 * @param filename 表格名
 * @param bookType 文件类型
 * @param styleFun(参数是当前表格ws) 样式函数方法
 */
function exportTableToExcel({ id, filename = '空', bookType = 'xlsx', styleFun = () => {} } = {}) {
  if (id) {
    var theTable = document.getElementById(id)
    var ws = XLSX.utils.table_to_sheet(theTable)
    styleFun(ws)
    var wb = XLSX.utils.book_new()
    XLSX.utils.book_append_sheet(wb, ws, 'SheetJS')
    var wbout = XLSX.write(wb, {
      bookType: bookType,
      bookSST: false,
      type: 'binary',
    })
    FileSaver.saveAs(new Blob([s2ab(wbout)], { type: '' }), filename + '.' + bookType)
  }
}

/**
 * 通过json渲染导出表格
 * @param title 标题
 * @param multiHeader多级头
 * @param header 头部
 * @param data 表格数据
 * @param filename 表格名
 * @param merges 合并单元格数组
 * @param autoWidth 宽度是否自适应
 * @param bookType 文件类型
 * @param styleFun(参数是当前表格ws) 样式函数方法
 */
function exportJsonToExcel(
  // 初始值
  {
    title = [],
    multiHeader = [],
    header = [],
    data = [],
    filename = '',
    merges = [],
    autoWidth = true,
    bookType = 'xlsx',
    styleFun = () => {},
  } = {}
) {
  // 文件名
  filename = filename || 'excel-list'
  // 表数据
  if (!isArrayFn(data)) {
    console.error('表数据不是数组类型，请检查data')
    return
  }
  data = [...data]
  // 头部
  if (isArrayFn(header) && header.length) {
    data.unshift(header)
  }
  // 标题向数组的开头添加一个
  if (isArrayFn(title) && title.length) {
    data.unshift(title)
  }
  // 多级头
  if (isArrayFn(multiHeader) && multiHeader.length) {
    for (let i = multiHeader.length - 1; i > -1; i--) {
      data.unshift(multiHeader[i])
    }
  }
  // 总数据
  // console.log(data)
  var ws_name = 'SheetJS'
  var wb = new Workbook(),
    ws = sheet_from_array_of_arrays(data)
  // 合并单元格
  if (merges.length > 0) {
    if (!ws['!merges']) ws['!merges'] = []
    merges.forEach((item) => {
      if (typeof item === 'object') {
        ws['!merges'].push(item)
      } else {
        ws['!merges'].push(XLSX.utils.decode_range(item))
      }
    })
  }
  // 设置宽度
  if (autoWidth) {
    /*设置worksheet每列的最大宽度*/
    const colWidth = data.map((row) =>
      row.map((val) => {
        /*先判断是否为null/undefined*/
        if (val == null) {
          return {
            wch: 10,
          }
        } else if (val.toString().charCodeAt(0) > 255) {
          /*再判断是否为中文*/
          return {
            wch: val.toString().length * 2,
          }
        } else {
          return {
            wch: val.toString().length,
          }
        }
      })
    )
    /*以第一行为初始值*/
    let result = colWidth[0]
    for (let i = 1; i < colWidth.length; i++) {
      for (let j = 0; j < colWidth[i].length; j++) {
        if (result[j]['wch'] < colWidth[i][j]['wch']) {
          result[j]['wch'] = colWidth[i][j]['wch']
        }
      }
    }
    ws['!cols'] = result
  }

  /* add worksheet to workbook */
  wb.SheetNames.push(ws_name)
  wb.Sheets[ws_name] = ws
  var dataInfo = wb.Sheets[wb.SheetNames[0]]
  // 暴露样式设置
  styleFun(dataInfo)
  // 导出excel
  var wbout = XLSX.write(wb, {
    bookType: bookType,
    bookSST: false,
    type: 'binary',
  })
  FileSaver.saveAs(
    new Blob([s2ab(wbout)], {
      type: 'application/octet-stream',
    }),
    `${filename}.${bookType}`
  )
}

/**
 * 通过table ID渲染导出表格
 * @param tableId 需要导出表格的ID
 * @param fileName 文件名
 * @param sheetName 表名
 */
function exportExcelMethod(tableId, fileName, sheetName) {
  tableToExcel(tableId, fileName, sheetName)
}
const tableToExcel = (function () {
  const uri = 'data:application/vnd.ms-excel;base64,'
  const template = `<html xmlns:x="urn:schemas-microsoft-com:office:excel"><head><xml><x:ExcelWorkbook><x:ExcelWorksheets><x:ExcelWorksheet><x:Name>{worksheet}</x:Name><x:WorksheetOptions><x:DisplayGridlines/></x:WorksheetOptions></x:ExcelWorksheet></x:ExcelWorksheets></x:ExcelWorkbook></xml><meta charset="UTF-8"></head><body>{table}</body></html>`
  const base64 = function (s) {
    return window.btoa(unescape(encodeURIComponent(s)))
  }
  const format = function (s, c) {
    return s.replace(/{(\w+)}/g, function (m, p) {
      return c[p]
    })
  }
  return function (table, filename, sheetname) {
    if (!table.nodeType) table = document.getElementById(table)
    const ctx = { worksheet: sheetname || 'Worksheet', table: table.innerHTML }
    const aTag = document.createElement('a')
    aTag.href = uri + base64(format(template, ctx))
    aTag.download = filename
    aTag.click()
  }
})()

// 导出方法
export default {
  exportExcelMethod,
  exportTableToExcel,
  exportJsonToExcel,
  formatJson,
}
